Remove Nth node from the end

ListNode.java

package com.interviewbytes.linkedlists;


public class ListNode {
    int val;
    ListNode next;

    ListNode(int x) {
        val = x;
    }
}

RemoveNthNode.java

package com.interviewbytes.linkedlists;


public class RemoveNthNode {

    public ListNode removeNthFromEnd(ListNode head, int n) {

        ListNode sentinel = new ListNode(0);
        sentinel.next = head;

        ListNode slow = sentinel;
        ListNode fast = sentinel;

        int i = 0;
        while (i <= n) {
            fast = fast.next;
            i++;
        }

        while (fast != null) {
            fast = fast.next;
            slow = slow.next;
        }

        slow.next = slow.next.next;

        return sentinel.next;
    }
}